A Comparison of Two State-Space Models of an Induction Machine Considering Different Sets of Winding Distribution Harmonics

The present paper compares two models of a low-power off-the-shelf induction machine. Each of them considers a specific set of winding distribution harmonics. One model takes into account the harmonic orders 1 and 17, while the other includes the orders 1, 5 and 11. These two sets of space harmonics are of particular interest as they give rise to a principal slot harmonic in the stator currents and produce unwanted torque oscillations. The model with space harmonics 1 and 17 has order 6, as does Park's. By contrast, its counterpart with harmonic orders 1, 5 and 11 features two additional states associated with rotor currents and directly linked to the harmonic torque ripple. The potential of each model with respect to drive control applications such as torque harmonic reduction is discussed.